Touch is one of the most intuitive human actions. Modern technology has capitalized on this fact by developing various products that respond to the human touch. For example, people can control different types electronic devices by contacting accompanying touch screen devices with either their finger or some other device (e.g., a stylus). Among other things, touch screen devices are used in automatic teller machines (“ATMs”) to permit a cash withdrawal, pen and tablet devices to enter data, and credit card signature devices to receive a customer's signature.
Many conventional touch screen devices have a display device, and a sensing arrangement that senses the coordinates of the point of contact. More specifically, contact at a specific location on the face of the display device generates a corresponding analog signal. This analog signal typically is sampled and converted (by an analog-to-digital converter) into a digital signal that is used by an electronic module (e.g., a microprocessor or microcontroller) to determine the coordinates of the point of contact.
Undesirably, however, the above noted analog signal can be distorted by signals generated by the display device. For example, the horizontal refresh signal, which can be produced many times per second (e.g., 24 to 30 times per second), commonly has the unintended effect of corrupting the analog signal. Consequently, if the analog signal is corrupted, then the coordinate data calculated from such analog signal can be corrupted. This corrupted data in turn adversely impacts the operation of the underlying system relying upon the touch screen device.